The invention relates in general to an odor-absorbing superabsorbing composition, a process for production of an odor-absorbing superabsorbing composition, a composite comprising an odor-absorbing superabsorbing composition, a hygiene article comprising a composite, chemical products comprising or based on an odor-absorbing superabsorbing composition or a composite, as well as the use of an odor-absorbing superabsorbing composition or of a composite in chemical products.
Superabsorbers are water-insoluble, crosslinked polymers, which are capable, by swelling and formation of hydrogels, of absorbing, and retaining under pressure, large amounts of aqueous liquids, in particular body fluids, preferably urine or blood. In general, these amounts of liquids amount to at least 10 times or even at least 100 times the dry weight of the superabsorber or of the superabsorbing composition in water. Because of these characteristic properties, these polymers principally find application in sanitary articles such as baby diapers, incontinence products or sanitary napkins. An encompassing overview of superabsorbers and superabsorbent compositions, their application and their production, is given by F. L. Buchholz and A. T. Graham (Editors) in “Modern Superabsorbent Polymer Technology,” Wiley-VCH, New York, 1998.
The preparation of superabsorbers generally occurs by radical polymerization of acid groups-carrying, mostly partially neutralized monomers in the presence of crosslinkers. Through the selection of the monomer composition, the crosslinkers and the polymerization conditions and the processing conditions for the hydrogel obtained after polymerization, polymers with different absorbent properties can be produced. Further possibilities are offered by the production of graft polymers, for example using chemically modified starches, celluloses and polyvinyl alcohol according to DE-OS 26 12 846.
DE 40 20 780 C1 discloses the post-treatment of superabsorbing polymers by post-crosslinking of the surfaces of the polymer particles. Through the post-crosslinking of the surface of the water-absorbing polymer particles, in particular the absorption capacity of the polymer particles under the effect of pressure is increased.
DE 199 09 653 A1 and DE 199 09 838 A1 describe powdery, surface-post-crosslinked, water, aqueous or serous liquids- or blood-absorbing polymers, which are based on acid groups-carrying monomers and which have been coated and post-crosslinked with a surface post-crosslinking agent and a cation in aqueous solution. The polymers disclosed in this prior art have advantageous absorption properties compared to conventional polymers, in particular a high permeability.
When wearing hygiene articles comprising absorbent polymers for longer wearing times, in particular if these have already partially absorbed body fluids such as urine, unpleasant odors can quickly occur, caused by the organic components of the urine and the body heat of the wearer. In order to counter this, numerous attempts have been made to achieve a binding of the odor-forming substances by means of corresponding additions to the hygiene article components which are different to the superabsorber, or to cover up this formed odor by means of perfume or the like. The incorporation of such substances in the form of components different to the superabsorber often has a negative effect on the performance of these hygiene articles while they are being worn. Thus, by means of the body fluids, often the odor-inhibiting or -reducing substances are transferred from the components different to the superabsorber into the superabsorber, such as by sponging in, where this has a negative effect on the performance of the superabsorber and thus of the hygiene article in total. Furthermore, it is disadvantageous in this concept, that the greater part of the body fluid given up to the hygiene article is located in the superabsorber anyway, and thus the odor-inhibiting or odor-reducing substances located outside the superabsorber can develop their effect less well.
DE 198 25 486 and DE 199 39 662 A1 disclose the combination of superabsorbers with cyclodextrin for odor-reduction. It can be seen from this otherwise highly promising approach, however, that the cyclodextrin only shows its odor-inhibiting effect in the superabsorber under particular conditions, namely if it is assured that the cyclodextrin is not separated again from the superabsorber. It is here preferred that the cyclodextrin is at least incorporated into the surface of the superabsorber article, in that cyclodextrin and/or cyclodextrin derivatives are covalently and/or ionically bound and/or incorporated therein.
Superabsorbers are further known from DE 103 34 271, which can comprise a plurality of odor binders homogeneously in the agglomerate. This document, which discloses an excellent solution for the use of superabsorber fine particles, does not, however, make available a superabsorber with odor-binding properties which is particularly suitable for application in hygiene articles. Besides an efficient and effective use of the odor binder, the superabsorber properties, which are influenced by the odor binder, are still in need of improvement.
In general, the present invention had the object of reducing or even overcoming the disadvantages arising from the prior art.
An object according to the invention consisted in providing a superabsorbing composition, which, on the one hand, has good odor-binding properties. It should, on the other hand, also be achieved that the performance of the hygiene article which comprises this odor-binding superabsorber composition is substantially as good as or even better than the performance of the hygiene article with a superabsorber which does not comprise the odor-binder as the odor-binding superabsorbing composition.
Furthermore, an object according to the invention consisted in providing a process for obtaining such a superabsorbing composition.
In addition, an object according to the invention consisted in providing a hygiene article which, in addition to good odor-binding properties, also has a good performance. Of particular significance in this context is the absorption rate of the hygiene article upon multiple wetting and the liquid distribution. Both properties are of significance in connection with a good wearing comfort of the hygiene article in addition to the odor reduction.
In addition, the present invention had the object of providing superabsorbing odor-binding substances, which can generally be incorporated into composites or also as composite or which can as such find application in chemical products or components thereof.
A contribution to the solution of the inventive objects is made by the subject matters outlined in the main and sub-claims, whereby the sub-claims represent preferred embodiments.